What students’ Facebook posts teach us about the identity challenge in field placements abroad

ABSTRACT

Facebook is a common tool that enables students to publicly express their emotions, thoughts, experiences, and knowledge. On the assumption that the personal narratives of students can provide deep insights into their learning processes during practical training programs, the article presents content analyses of Facebook posts written by Israeli students who participated in an international social work field placement program in India. Content analysis of the students’ posts reveals that they grappled with their personal and professional identities as part of the learning process that occurred while they were formulating their professional identity as social workers. The analysis elicited three main themes: (1) awareness of the national identity; (2) exploration of other identities (personal, professional, and global); and (3) an attempt to contain multidimensional identity. The students discussed the main challenges they faced in the process of formulating an identity that will enable them to engage in international social work, and they described the fluctuations that occurred in those identities. The results show how public Facebook posts can be used as a tool to shed light on the contribution of social work education in international field placements, and provide insights into the learning processes that students experience in field placements abroad.     

基于人口迁移的中国城市体系演化预测研究

从中国城市化的本质———人口迁移网络出发，考虑所有城市空间单元以及城市间人口迁移联系在内，开展人口迁移和城市体系的综合性研究，探讨中国城市体系演化机理，将新经济地理学理论拓展到多区域，引入地理空间异质性，构建空间参考明确、全域均衡、空间单元之间存在明确人口迁移机理的城市体系模型。通过实证检验，该模型的模拟结果较为接近实际情况，模型拟合精度较高，可以用于城市体系演化预测。根据目前中国实际国情和国家政策导向，本文在三种大的城市化情景下根据中国各城市间人口迁移来预测中国未来城市体系的演化，即把整个城市体系视作一个通过人口迁移相互联系的网络整体来预测城市人口变化情况，从而为国家新型城镇化规划的流动人口管理、公共服务改进和城市等级体系规划等方面的政策制定提供现实依据。     

中国的家庭结构转变--来自居住方式与人口因素的作用

基于历次人口普查数据,利用SOCSIM微观模拟方法将家庭转变的关键影响因素分解为人口因素和居住方式因素两个方面,并进一步将人口因素分解为人口惯性、生育率、死亡率和结婚率四个层面进行计量分析.结果发现,当前人口变动相对稳定,较小的波动使其在家庭转变中的贡献率相对较小,而居住方式的影响相对较大;对人口因素的进一步分解还发现,人口惯性及生育率水平的作用相对更大,生育率水平、结婚率水平带来的影响与人口因素的总影响方向是一致的,均提高了一人户、一代户、二代户的人口比重,降低了三代及以上户的人口比重.与之相反,死亡率的影响与人口因素的总影响方向是相反的.     

文化生态学视角的文化景观研究

通过分析文化景观研究所面临的复杂性问题及总结我国文化景观研究保护的现状，从文化生态学的突起对文化景观研究方法的再定义，到通过分析文化生态学的立场与方法模式，尝试寻找出深化文化景观研究的方向，并进行论证，即文化景观的时空性、环境响应模式、生态演替与拓展适应以及文化景观的“力场”分析，为未来文化景观及其发展与保护的深入研究抛砖引玉。     

特低渗透油藏压裂水平井新型布井方式研究

考虑长庆油田特低渗油藏地貌特征和储层各向异性，提出了一种压裂水平井新型布井方式。从钻井和油藏两个角度论证新型布井的可行性。丛式井技术可确保压裂水平井新型布井的顺利实施。利用油藏数值模拟方法，分别从单井产能、阶段采出程度、含水率、波及面积等方面评价了压裂水平井新型布井在交错、菱形和矩形井网中的开发效果。研究表明，新型布井与常规布井在交错井网中具有相同的开发效果；菱形和矩形井网中，新型布井可以提高阶段采出程度、单井产能和相对波及面积，降低相同采出程度对应的含水率。新型布井在菱形井网（矩形井网）30 a 的相对波及面积和采出程度分别提高6.00%（10.00%）和0.96%（1.60%），含水率95% 的采出程度提高1.05%（1.50%）     

CO2 驱替沥青质原油长岩芯实验及数值模拟

针对CO2 驱油过程中出现的沥青质固相沉积现象，综合考虑注气过程中沥青质在多孔介质中的沉积、吸附及堵塞效应，建立了CO2 驱替含沥青质原油多相多组分渗流模型。以长岩芯实验为基础，拟合实验数据表明使用本文建立的模型计算的采收率与实验值更接近。同时对CO2 气驱过程中沥青质沉积规律进行了探讨，模拟研究表明，注入CO2 过程中，沥青质沉积首先发生在注入端；沥青质吸附也首先发生在注入端，但随着注入气量的增加，存在解吸附过程；沥青质沉积前缘与注气前缘一致，说明注入CO2 是导致原油中的沥青质沉积的主要原因。     

社会主义核心价值观的网络培育模式新探——基于网络实践活动进程视角

随着科学技术的迅速发展,网络社会随之成为人们生存的新环境.在这种新环境下,社会主义核心价值观的培育如何"满载而归",不仅是理论难题,更是现实困扰.而人的网络实践活动进程为社会主义核心价值观培育模式的研究提供了新视角.从人的网络实践进程出发可将培育活动发生场域确定为"器物"场域、"界面"场域、"网络空间"场域、"网络生活世界"场域,根据每个场域的特征和中心问题,有针对性地实施主体教育模式、感知吸引模式、信息耦合模式、精神升华模式等培育模式,四种模式相互联系、相互影响,以此抢占主流意识形态传播的制高点和新阵地.     

Sufficient m-out-of-n (m/n) bootstrap

Traditional resampling methods for estimating sampling distributions sometimes fail, and alternative approaches are then needed. For example, if the classical central limit theorem does not hold and the naïve bootstrap fails, the m/n bootstrap, based on smaller-sized resamples, may be used as an alternative. An alternative to the naïve bootstrap, the sufficient bootstrap, which uses only the distinct observations in a bootstrap sample, is another recently proposed bootstrap approach that has been suggested to reduce the computational burden associated with bootstrapping. It works as long as naïve bootstrap does. However, if the naïve bootstrap fails, so will the sufficient bootstrap. In this paper, we propose combining the sufficient bootstrap with the m/n bootstrap in order to both regain consistent estimation of sampling distributions and to reduce the computational burden of the bootstrap. We obtain necessary and sufficient conditions for asymptotic normality of the proposed method, and propose new values for the resample size m. We compare the proposed method with the naïve bootstrap, the sufficient bootstrap, and the m/n bootstrap by simulation.     

钻井实体膨胀管纵向金属流动的试验研究

为了研究井眼中钻井实体膨胀时的力学环境,选用35CrMo钢管,将金属塑性加工领域的网格法引入石油管程领域,对实体膨胀管的纵向金属流动规律进行了试验研究,发现膨胀管膨胀过程中存在明显的纵向金属流动不现象,并对造成这一现象的原因进行了分析。同时对膨胀后的管子材料进行了金相分析,金相分析结果证实了网法的分析结果,说明了将网格法引入石油工程领域是可行的。     

Simultaneous confidence intervals for comparing several inverse Gaussian means under heteroscedasticity

Recently, Zhang [Simultaneous confidence intervals for several inverse Gaussian populations. Stat Probab Lett. 2014;92:125–131] proposed simultaneous pairwise confidence intervals (SPCIs) based on the fiducial generalized pivotal quantity concept to make inferences about the inverse Gaussian means under heteroscedasticity. In this paper, we propose three new methods for constructing SPCIs to make inferences on the means of several inverse Gaussian distributions when scale parameters and sample sizes are unequal. One of the methods results in a set of classic SPCIs (in the sense that it is not simulation-based inference) and the two others are based on a parametric bootstrap approach. The advantages of our proposed methods over Zhang’s (2014) method are: (i) the simulation results show that the coverage probability of the proposed parametric bootstrap approaches is fairly close to the nominal confidence coefficient while the coverage probability of Zhang’s method is smaller than the nominal confidence coefficient when the number of groups and the variance of groups are large and (ii) the proposed set of classic SPCIs is conservative in contrast to Zhang’s method.